Electronic Potting Compound

[john_morris_uk]

I am about to make a ground isolator for the earth on the ATU of my SSB set up.

I have bought the high voltage capacitors and I will solder them together with some leads suitable coming off them etc.

I was thinking of encapsulating them in a potting compound to ensure that there's no strain on the joints etc but am wondering if I should buy some special potting compound or just use epoxy resin?

I am also concerned that the epoxy will probably get quite warm as it sets. My only solution is that I could chill it in the fridge as it sets?

Any thoughts and any suggestions as to where I can buy a small quantity of potting compound from or is epoxy OK??

 

[savageseadog]

You can use epoxy but it won't bond to the insulation of the wires so moisture can creep down the interface. There are specialist conformal coatings which are various forms of rubber. I would suggest silicone sealant as the cheapest option though.

 

[nigelmercier]

Potting compound is often epoxy, probably with a slow catalyst.

I use normal polyester resin for potting. If a large volume, just do it in layers.

Silicone is also good, but single pack (in a tube) takes a long time to cure in volume.

If you want the real stuff, you can get it from CPC or a smaller pack on Amazon: http://amzn.to/Pv1lxP

 

[DownWest]

If you cool epoxy it will not go off.
There is special casting polyester resin that does not overheat, but I would just use a gob of silicone over the terminals.

One thing I do use a lot of is SikaFlex 11FC, a PU glue/mastic. About €6 a tube in the local B&Q, sticks to just about anything and remains a bit flexable. It would do for this job.

 

[Dabhand]

Use an electronics grade of silicone sealant if possible, bathroom / kitchen stuff is slightly acidic.
From memory going back a few years, Dow Corning 3140 is one of the best, flexible with good adhesion. I have used it to coat terminals with up to 12kV on them.